Vitamin D Serum Levels
Conditions
Brief summary
Seasonal variations in vitamin D status will be determined on a cohort of Slovenian adults using longitudinal study design, and association between vitamin D status and different Caucasian phototypes, skin colour and melanin index investigated .
Interventions
None listed
Sponsors
VIST - Faculty of Applied Sciences
Slovenian Research Agency
Valens Int. d.o.o., Slovenija
Institute of Nutrition, Slovenia (Nutris)
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Signed Informed consent form (ICF), * Caucasian race * Age between 18 and 65 years at the time of the signature of Informed consent form (ICF), * Willingness to avoid a consumption of any food supplements containing Vitamin D during the study, except the ones prescribed by the study researchers, and to avoid use of solarium or other artificial UVB sources * Willingness to follow all study procedures
Exclusion criteria
* Pregnancy or breastfeeding, * Known or suspected allergy to any ingredient of the tested products in Part 2, * Pronounced avoidance of sunshine (eg reporting of allergy to the sun) * Use of food supplements containing Vitamin D or fish oil or omega 3 fatty acids in last three months prior to inclusion, * Special dietary habits used by a small part of the population (veganism, low-carb hihg-fat diet, caloric restriction diet, note: vegetarians are not excluded) * Diets prescribed by the medical profession * Disorders of the kidneys, thyroid, digestive tract, osteoporosis and other bone diseases, skin diseases * Other diseases and conditions that affect the absorption and synthesis of vitamin D * Exposure to stronger sunlight in the last three months prior to engaging in a survey (travel to countries with stronger sunshine, use of solarium), * The consumption of margarine or plant substitutes for milk / milk products several times a day, as these foods are most often enriched with vitamin D, * Visiting the solarium in the last three months before joining the survey, * Mental incapacity that precludes adequate understanding or cooperation.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Difference between vitamin D serum levels in winter and in summer season will be determined | 2 years | Vitamin D serum level will be measured once in winter (December - January) and once in summer season (August-September) for each individual. The study will be performed over two consecutive years. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Correlation of vitamin D serum levels with Fitzpatrick skin phototype | 2 years | Fitzpatrick skin phototype will be determined using Fitzpatrick self-evaluation questionnaire in combination with expert assessment in August-September. |
| Correlation of vitamin D serum levels with skin colour measured in CIE Lab colour space | 2 years | Skin colour will be measured in CIE Lab colour space on inner and outer side of the upper arm. The measurement will be performed in August-September. |
| Correlation of vitamin D serum levels with melanin index | 2 years | Melanin index will be measured on inner and outer side of the upper arm. The measurement will be performed in August-September. |
Countries
Slovenia
Outcome results
None listed